> > > >

1945 Theatre Catalog, 4th Edition, Page 349 (325)

1945 Theatre Catalog, 4th Edition
1945 Theatre Catalog
1945 Theatre Catalog, 4th Edition, Page 349
Page 349

1945 Theatre Catalog, 4th Edition, Page 349

sary to hook it into a public address system or a music distribution system.

A control on the amplifier panel provides for quick switching between film reproduction, microphone, and non-synchronous record turntable. Other knobs adjust the volume for monitor speaker, microphone, and turntable.

Correct voltage and current necessary for the sound system, with the exception of that received directly from the power line, are furnished by tube rectifiers.

A sound system is only as good as the backstage speakers which provide the final step in the process of sound-film reproduction. The permanent-magnet Duophonic loudspeaker combinations for the Westrex Master system are superior to any pre-war speaker combinations.

Energy radiated backwards from the low-frequency units is used to reinforce the overall efiicienCy of the new Duophonic combinations. It will no longer be necessary to use drapes to eliminate backstage reverberation. With the same amount of electrical energy, Duophonics deliver twice as much acoustic energy to the auditorium compared with prewar systems.

The new baHle designs increase realism-make the ffscreen presence" more life-like than ever. The illusion is almost perfect. Sounds appear to come from the screen itself and not from behind it.

Diderent sizes of bafHes are available with different combinations of high- and low-frequency units. The ultra-highpowered speaker systems for the largest theatres may contain two high-frequency receivers on one horn or as many as six low-frequency units.

(For a more complete discussion of this equipment, see Altec-Lansing Voice of the Theatre model A-4, for medium theatre, and Voice of the Theatre model A-5, for small theatres.)

Westrex Standard

The Westrex Corporation offers a new, simplified, low-priced sound system, the Westrex Standard.

Exhibitors whose budgets are limited and who want faithfulness of Western .Electric quality round reproduction can now meet both these conditions with the Westrex Standard.

The Standard has quality and ruggedness that have never before been attained in comparable equipment. The entire system has been efficiently simplihed to hold the cost at a moderate price level, and yet overall performance is superior to most pre-war, high-priced systems.

Extensive use is made of new ideas and components which have been developed by intensive wartime research in Western Electricls greatly expanded laboratories and manufacuring plants.

Noteworthy features of the W'estrex Standard are the following: an improved method of reducing mechanical fiutter, efiicient amplification, and improved conversion of electrical energy into acoustic energy.

These are all features that the alert exhibitor will recognize as necessary to attract increased patronage.

The Standard reproducer uses the hydro dutter suppressor to reduce mechanical fiutter. It is Western Electricis solution of one of the most vexing prob l945-THEATRE CATALOG

lems in sound reproduction: the irregular movement of the film as it passes the scanning beam. This is how it works: Two film-pad rollers coordinated by a spring respond sensitively to the pressure of the film as it passes over the lower roller. The lower roller arm is cone nected with a piston which moves in a special damping fiuid. Even the most minute variations in speed will tend to add a slight amount of slack to the film as it loops around the impedance drum. The hydro flutter suppressor then acts instantly and holds the film snugly around the drum, reducing the flutter by more than one-half the minimum standard of 0.15 percent set by the Academy of Motion Picture Arts and Sciences.

A hand wheel, as a convenient aid when threading the film, is mounted on the motor shaft. A glance at the film path reveals the simplicity of threading operation. There is only one sprocket and two pad rollers in the film path. White interior walls and a threading light add to the ease of threading.

The Standard reproducer uses a shockmounted, pre-focused exciter lamp, operating from an ac. power source. It is designed to reduce hum to the lowest level. The lamp can be adjusted vertically and laterally to insure perfect alignment with the lens tube.

The long life, highesentitivity, photoelectric cell has an extremely low noise level when compared with its output of useful sound energy. It is shock-mounted and completely enclosed in a partition with a separate cover. This cover protects the cell from oil which might be spilled from above through excess lubrication.

A fool-proof switch for change-over of the sound system between machines is located in a convenient place on the front of the reproducer unit. This is a distinct improvement over the old,

wall-mounted type of change-over by extension rods.

The motor is ball-bearing and oversized to provide a safe margin of power. The v-belt drive is short and efficient.

One housing contains all necessary amplification. The 15-watt power amplifier is fed by a coaxial cable from the photo-electric cell. Included in the same housing is the power unit for furnishing filament and plate voltages to all tubes. These units comprise an integral assembly mounted on a single chassis.

The well-known negative feed-back circuitea development of Western Electric and Bell Telephone Laboratoriesprovides a self-compensating correction for harmonic sound distortion. The distortion in this amplifier is less than 2 percent. Transformers, coils, condensers, and resistors are designed to reduce the possibility of failure. Component parts which would be affected by high temperature and humidity have been specially treated to withstand such climatic conditions.

The Westrex Standard sound system can be adapted for use with any standard make of projector.

The Westrex Standard uses a duplex loudspeaker in which a miniature highfrequency, multi-cellular horn is mounted coaxailly with the low-frequency speaker. This combination gives excellent distribution of sound throughout the auditorium.

There are two speaker combinations: one for theatres having up to 600 seats, and another for houses seating up to 1,200, These new speaker combinations are twice as efficient as similar pre-war units and aid in giving a screen fipresence" and auditorium coverage, which are salient features of the post-war Westrex Standard.

(For further speaker details, see the discussion of Altec-Lansing Voice of the Theatre models.)


traumas: , i

a-*" 44'
1945 Theatre Catalog, 4th Edition, Page 349